Superfetation in the viviparous fish Heterandria formosa (Poeciliidae)

• Published in: Journal of morphology (1931) Vol. 280; no. 5; pp. 756 - 770
• Main Authors: Guzmán‐Bárcenas, María Guadalupe, Uribe, Mari Carmen
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.05.2019
• Subjects: Animals; Cyprinodontiformes - anatomy & histology; Cyprinodontiformes - embryology; Cyprinodontiformes - physiology; Embryo, Nonmammalian - anatomy & histology; Embryo, Nonmammalian - physiology; Embryonic Development; Female; fertilization; Ovary - anatomy & histology; Ovary - cytology; Pregnancy; simultaneous broods; sperm storage; Superfetation - physiology; Viviparity; Viviparity, Nonmammalian - physiology; simultaneous broods; Viviparity; sperm storage; fertilization; embryonic development
• ISSN: 0362-2525; 1097-4687
• DOI: 10.1002/jmor.20982

Heterandria formosa is a viviparous poeciliid native of the southeastern of United States of America. H. formosa exhibits unique reproductive features as: (a) production of extremely small eggs with scarce quantity of yolk (microlecithal eggs), (b) consequently, a high level of matrotrophy and development of a complex follicular placenta, (c) ovarian sperm storage that allows the continuous fertilization of oocytes and production of offspring and (d) development of high degree of superfetation. The degree of superfetation refers to the number of broods in different simultaneous stages of gestation. Morphological evidence of the degree of superfetation in H. formosa has not been documented. Therefore, and because of the general interest in the complex process of superfetation, the goal of this study is to morphologically define the degree of superfetation of H. formosa through two procedures: (a) histological analysis of entire ovaries in gestation and (b) dissection of visible embryos and the histological analysis of the remaining ovarian tissue. Results indicate that H. formosa can gestate up to seven broods at the same time. Superfetation degree in Heterandria formosa. (a) Five broods of embryos obtained by dissection with dissecting microscope were identified, in stages from optic cup (S6) to very‐late eyed embryo (S10). (b, c) Two histological sections of the remaining ovarian tissue with embryos in stages of blastodisc (S4) and shield/primitive streak (S5), both broods not visible by dissection. Bar = a: 1 mm, b: 200 μm, c: 200 μm.